JPH0590029U - Failure detection device for shift lever position sensor - Google Patents

Abstract

(57) [Abstract] [Purpose] To detect an OFF failure of a position sensor that detects an operating position of a shift lever of a vehicle transmission. [Configuration] When the shift lever is operated to switch over adjacent switching positions, for example, the shift lever is moved from the N position for neutral to the D ₃ position for automatic shifting from the first speed to the third speed.
Speed through when switching operation to D ₄ position for the automatic transmission of 4-speed, determines the presence or absence of off-failure of the sensor switches for D ₄ on whether D ₄ signal is generated from the position sensor in the switching換途.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a position sensor failure detection device mainly applied to a shift lever of an automatic transmission for a vehicle.

[0002]

[Prior Art]

 Conventionally, in automatic transmissions that are controlled by an electronic control circuit, the position sensor detects the operating position of the shift lever, and the signal from the sensor is input to the electronic control circuit to respond to the operating position of the shift lever. It is common to perform shift control in this mode. Here, the shift lever is configured to be linearly switched to a plurality of positions such as a parking position, a reverse position, a neutral position, an automatic speed change position, and a low speed holding position. A position sensor is made up of multiple switches that turn on when operated, and the operating position of the shift lever is determined by which switch is turned on. Japanese Patent Laid-Open No. 61-61-1999 discloses that when any two or more of a plurality of switches forming a position sensor are simultaneously turned on, it is determined that the position sensor has failed and appropriate fail-safe measures are taken. It is known from Japanese Patent No. 157441.

[0003]

[Problems to be solved by the device]

 The above-mentioned is for detecting an ON failure such as welding of the switch constituting the position sensor.However, since an OFF failure such as disconnection of the switch may occur, it is desirable to be able to detect the OFF failure. ing. It is an object of the present invention to provide a device that meets this need.

[0004]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a vehicle speed change gear that is switchable to at least three positions of a first position, a second position and a third position and is switched from a first position to a third position via a second position. In a device that detects a failure of a position sensor that detects the operating position of a shift lever of a machine, when the shift lever is switched from the first position to the third position, the position sensor switches from the position sensor to the second position during the switching operation. It is characterized in that it is provided with means for judging whether or not a position sensor has failed by judging whether or not a corresponding signal is generated.

[0005]

[Action]

 If the switch for the second position of the position sensor has a failure, the signal corresponding to the second position will not be output even if the shift lever is in the second position during the switching operation from the first position to the third position. It does not occur, so that an off failure of the switch for the second position is detected.

[0006]

【Example】

 Referring to FIG. 1, reference numeral 1 denotes an electronic control circuit (hereinafter referred to as ECU) for controlling an automatic transmission for a vehicle, which sends a signal from a position sensor 3 for detecting an operation position of a shift lever 2 to an ECU 1. By inputting, the shift control of the speed changer is performed in the mode corresponding to the operation position of the shift lever 2.

The shift lever 2 has a “P” position for parking, an “R” position for reverse, an “N” position for neutral, and a “D ₄ ” that automatically shifts from 1st speed to 4th speed. The position sensor 3 is configured to be directly switched between a position, a "D ₃ " position for automatic 1st to 3rd speed shifting, and a "2" position for holding 2nd speed. configured in "P", "R", "N" the "D _4", "D _3" of the total of six to on at each position of the "2" switches 3a ... 3f, the "P" position serving oN signal switches 3a " P "signal," R "on signal serving" R "signal from the position the switch 3b," N "," N "signal serving as on-signal of the switch 3c is located in the the" D ₄ "position serving on signal of the switch 3d" D ₄ "signal," D ₃ "," D ₃ "signal serving as an oN signal of the switch 3e is located," 2 "position Serving on signal of the switch 3f "2" signal is to be input to each ECU1 is.

The ECU 1 has a diagnostic function of detecting a failure of the position sensor 3, and is configured to operate an indicator 4 such as an alarm lamp when a failure is detected.

When the shift lever 2 is operated to switch over the adjacent switching position, for example, the failure of the position sensor 3 is detected by, for example, the “D ₄ ” position between the “N” position and the “D ₃ ” position. It is determined whether or not the "D ₄ " signal is input during the switching operation that exceeds the setting. The details are as shown in FIG. 2, and when the "N" signal and the "D ₃ " signal are input (S1, S2), it is determined whether or not the "D ₄ " signal is input during the process. (S3). In this case, if the “D ₄ ” switch 3d is normal, it is judged to be normal because the “D ₄ ” signal is input (S4). On the other hand, the switch 3d has an off failure due to disconnection of the signal line or the like. If so, since the "D ₄ " signal is not input, it is determined that the "D ₄ " switch 3d is off (S5).

This program for detecting a failure detects an OFF failure of the “R” switch 3d when switching between the “P” position and the “N” position, and the “D ₄ ” position and the “2” position. The same can be applied to the detection of the OFF failure of the "D ₃ " switch 3e during the switching operation between the and.

[0011]

[Effect of the device]

 As is clear from the above description, according to the present invention, it is possible to easily and accurately detect an OFF failure such as a disconnection of the shift lever position sensor depending on the presence or absence of a signal during the shift lever switching operation.

[Brief description of drawings]

FIG. 1 is a system diagram of an example of the device of the present invention.

FIG. 2 is a flowchart showing a program for detecting a failure.

[Explanation of symbols]

1 ECU 2 Shift lever 3 Position sensor

Claims (1)

[Scope of utility model registration request] 1. An operating position of a shift lever of a vehicle transmission, which is switchable to at least three positions of first, second and third, and is switched from a first position to a third position via a second position. In a device for detecting a failure of a position sensor that detects a position, whether a signal corresponding to the second position is generated from the position sensor during the switching operation when the shift lever is switched from the first position to the third position. A failure lever detecting device for a shift lever position sensor, comprising means for judging whether or not there is a failure in the position sensor.